1. Field of the Invention
The present invention relates to a method and apparatus for generating a three-dimensional image or stereograph having one file structure, and recording the image on a recording medium, and a recording medium that stores the three-dimensional image data and, more particularly, to a method of generating a three-dimensional image or stereograph having one file structure, which allows to store data of a three-dimensional image or stereograph in one file, and allows processing of stereo image data for respective files, and recording the image on a recording medium, an apparatus for recording the three-dimensional image data and recording the image data on a recording medium, and a recording medium that stores the three-dimensional image data.
2. Description of the Related Art
Various proposals have been made about a method of recording photographic information containing three-dimensional information by taking photos of an object, and observing a three-dimensional image by reproducing the photographic information. Of such proposals, a so-called binocular type stereographic system which records two images having parallax corresponding to that between the viewpoints of the right and left eyes of a person, and allows the user to observe the two images by the right and left eyes is known. Since the binocular type stereographic system uses a photographing apparatus with a simple structure, it can provide a low-cost photographing apparatus and reproduction apparatus, and allows effective observation of a three-dimensional image. Hence, the binocular type stereographic system has been utilized to date for so long.
In this binocular type stereographic system, various display systems are available. For example, when many people simultaneously observe a large screen, a polarizing projection system that uses polarizing glasses, and a time division display system that uses shutter glasses are used. Since these systems are bulky and expensive, they are rarely used except for special business purposes. For so-called personal use, a stereoscopic view system that allows stereoscopic view of a stereo image pair as the most basic and classic method is known, although the number of persons who can observe at the same time is limited to one. Today, this system is still prevalently used as a very low-cost system that can observe a clear image.
The stereo image pair will be explained in detail below. Two images, i.e., an L image corresponding to an image observed when an object is viewed from the left eye viewpoint, and an R image corresponding to an image observed when the object is observed from the right eye viewpoint are normally juxtaposed with a small gap, and when a person simultaneously observes these images, he or she can recognize them as a single three-dimensional image.
As a simplest photographing apparatus of such images, a system that combines 35-mm single-lens reflex camera with a stereo adapter has prevailed. In this system, two, R and L images are stored in practice in a single standard image frame having an aspect ratio of 3:2. Therefore, each of the R and L images, i.e., two images containing three-dimensional information to be observed normally has a frame having an aspect ratio of about 3:4.
In this specification, two, R and L images which are juxtaposed spatially, i.e., on an image plane, and contain single three-dimensional image will be referred to as a stereo image pair. Note that the aforementioned practical configuration (numerical values of aspect ratios and the like) is merely an example. But for the sake of simplicity, the following explanation will be given under the condition that the above practical values are taken as an example unless otherwise specified.
This stereo image pair has very practical features:
(1) These images can be recorded, printed, transferred, and so forth without requiring any special system.
(2) These images can be directly stereoscopically observed as long as an appropriate condition is satisfied. That is, no special apparatus is required upon observing a three-dimensional image by matching right and left images.
Especially, in feature (2), “match of right and left images” is defined as a state wherein R and L images are normally captured by the right and left eyes, and are recognized not as two different images but as a single three-dimensional image. In image match, the right and left images can be matched using a so-called “parallel view method” in which the lines of sight are parallel to each other upon observation, as long as images are printed with an appropriate size (more specifically, the width is slightly smaller than a value twice the eye width: 10 to 13 cm) and have a “parallel layout” (the L image is set on the left side, and the R image on the right side). The “parallel view method” is a method for observing a three-dimensional image by directly observing R and L images while maintaining the lines of sight nearly parallel to each other like in a case wherein a person looks at an image which is far away, without the aid of any devices, although some practices are required in some individuals. Also, in image match, a “cross layout” in which the right and images are juxtaposed, but their positions are replaced unlike in the “parallel view method” is available. In this “cross layout”, there is no limitation as to the printed image size, and three-dimensional observation is also directly attained by a “cross-eye view method” in which the lines of sight are crossed. However, since the “cross-eye view method” suffers eye fatigue upon observation and unnaturalness (so-called miniascape phenomenon) upon three-dimensional observation more than the “parallel-view method”, the parallel layout is more prevalently used.
In either case, a stereo image pair which has two large features: (1) system independence and (2) direct observation will remain used since its value is projected to be reevaluated as so-called media mix such as proliferation of the Internet, digital cameras, and the like progresses.
Hence, the present applicant has proposed a technique associated with an observation method and apparatus (viewer) which give different shifts to R and L images so as to allow easy high-quality observation with high natural stereoscopic feeling using an SPM (Stereo Pair in Multimedia)) as a digital stereo image pair (Japanese Patent Application No. 2000-115357). In this technique, identical images are normally displayed on two display devices (monocular mode), but when an SPM is read out from a memory card and is displayed, right- and left-eye images undergo different shift processes by a stereo image pair shift processor, and image signals that have undergone the shift processes are displayed on the display devices as right- and left-eye images (stereo mode). With the shift processes, an L image of the SPM on the left-eye image side matches an R image of the SPM on the right-eye image side as one three-dimensional image, and a high-quality three-dimensional image with high natural stereoscopic feeling can be easily observed.
On the other hand, as a digital still camera (digital camera) that can sense a stereo image, a camera described in Jpn. Pat. Appln. KOKAI Publication No. 5-30538 devised by the present inventors is known. In this camera, two imaging systems (lenses+pickup units) sense R and L images, stereo pair code data (data indicating a stereo image, L or R identification information, and the like) are individually appended to respective images, and the sensed images are recorded on a recording medium, e.g., a memory. This camera is evaluated as an excellent camera which can easily sense a stereo image.
However, the digital camera of the above reference suffers the following problems.
(a) Since two imaging systems are required, the camera indispensably becomes bulky and expensive.
(b) Since the obtained stereo image is different from the SPM (stereo pair in parallel layout), it must be additionally converted into an SPM to obtain the SPM.
If a conventional stereo adapter is combined with a general (single-lens) digital camera, it may seem that these problems (a) and (b) can be solved. However, in this case:
(c) No data that pertains to stereo as well as data indicating that the image are a stereo image is appended. Therefore, when normal two-dimensional (non-stereo) images are stored together with stereo images, their management becomes complicated. Also, it is impossible to automatically execute image shift processes upon reproduction in the viewer of the above application.
Especially, this problem (c) may be solved by appending stereo pair codes to image files that record R and L images. However, such measure cannot be taken in practice since a conventional system that combines a single-lens pickup camera with a stereo adapter cannot process R and L images as independent images.
In addition to the above problem, even when such stereo image can be recorded by some method, we have a problem resulting from the handling structure of such images as per:
(d) when an external stereo adapter is attached to the imaging system of a normal single-lens camera, phenomena of overlap of images, darkened image portion, and the like cannot be avoided due to attachment of the adapter. That is, when a small F value is selected, i.e., when the selected stop value is at the full-open side, as shown in FIG. 1A, R and L image may overlap each other. On the other hand, when a large F value is selected, i.e., the selected stop value is at the stop-down side, as shown in FIG. 1B, the portion between R and L images is darkened.
Furthermore, (e) one stereo image information is distributed to a plurality of image handling units (files). Therefore, when such images are handled by a versatile recording/reproduction apparatus or transmission apparatus, their stereo pair codes cannot be recognized, and all these images are handled as independent images. As a result, only one frame of R and L images may be inadvertently erased or transmitted.